The invention relates to auxiliary cranks for plug doors of railway house cars. Plug doors typically have a pair of rotationally driven top operating cranks with a top auxiliary crank mounted therebetween to minimize the danger of the cranks separating from a c-shaped longitudinal top retainer in which they move and any door displacement as a result thereof.
The prior art has recognized the need for auxiliary cranks in U.S. Pat. Nos. 3,913,269 to Ross, 4,129,965 to Reynolds, and 4,142,328 to Saffrahn. The Ross U.S. Pat. No. 3,913,269 utilizes only a single roller on the auxiliary crank to engage the inside of the c-shaped longitudinal retainer. The Reynolds U.S. Pat. No. 4,129,965 utilizes what it terms is a "shuttle means". The structure includes a "load bearing skirt" for engagement only "in case of failure" with the c-shaped retainer's lower flange at a location inside of the engagement of a front sled and the downwardly extending front flange. In this patent the load bearing skirt "in case of failure" will act as a fulcrum about which the front sled will pivot with great force against the inside of the front flange thereby tending to distort it to a point of displacement of the plug door. The Saffrahn U.S. Pat. No. 4,142,328 utilizes a front roller and a bottom sled engaging the c-shaped retainer inside of the location of engagement of the front roller with the inside of the c-shaped longitudinal retainer. Saffrahn's structure, accordingly, can create a moment of force about the bottom sled tending to pivot and separate the auxiliary crank from the c-shaped longitudinal retainer and thereby displace the door.